Exposure profile effects on the concentration of FreonŽ-113 in exhaled air.
Dalamagas-D; Coffey-CC; Zhuang-Z; Lawrence-RB
J Int Soc Respir Prot 2002 Spring/Summer; 19(1-2):37-48
End-exhaled breath concentrations of 1,1,2-trichloro-1,2,2-trifluoroethane (Freon-113) have been used as a measure of respirator performance. This study investigated whether end-exhaled breath concentration is significantly affected by the "leak profile" and thereby not representative of the concentration to which the wearer was exposed. Four subjects participated in three different phases. End-exhaled air samples were collected and analyzed after each 30-minute test. Phase 1 consisted of four scenarios supplying: (a) 500 ppm Freon-113 only during the first minute, (b) 500 ppm exposure only during the last minute, (c) 33 ppm during the first 15 minutes, and (d) 33 ppm during the last 15 minutes. Phase 2 consisted of supplying 500 ppm in two scenarios: (a) during the first six minutes, and (b) during the last six minutes. Phase 3 consisted of two scenarios supplying: (a) 500 ppm for two minutes at the beginning, middle, and end of the test, and (b) 100 ppm continuously. For two subjects in Phase 1, the means of scenario (b) were statistically higher than those for the other three scenarios; this could have been attributed to high intra-subject end-exhaled breath concentration variability. No significant difference was found between subject means for the scenarios in Phases 2 and 3. A significance level of alpha = 0.05 was used for all analyses. It was concluded that different exposure scenarios, having identical time-weighted exposures, produced consistent end-exhaled breath concentrations and Freon-113 can be used as a measure of air-purifying respirator performance.
Air-purifying-respirators; Time-weighted-average-exposure; Testing-equipment; Respiration; Respirators; Respiratory-protective-equipment; Laboratory-testing; Equipment-design; Equipment-reliability; Exposure-methods; Breathing; Face-masks; Leak-detectors; Leak-prevention; Fluorocarbons; Statistical-analysis;
Author Keywords: Freon-113; end-exhaled air; respirator performance; leak profile
National Institute for Occupational Safety and Health (NIOSH), Division of Respiratory Disease Studies, 1095 Willowdale Road, Morgantown, WV 26505-2888, USA
Research Tools and Approaches: Control Technology and Personal Protective Equipment
Journal of the International Society for Respiratory Protection